function checkNum(thisChar) {

	if((thisChar != '0') &&
		(thisChar != '1') &&
		(thisChar != '2') &&
		(thisChar != '3') &&
		(thisChar != '4') &&
		(thisChar != '5') &&
		(thisChar != '6') &&
		(thisChar != '7') &&
		(thisChar != '8') &&
		(thisChar != '9')) {
		
		return false;
		
	} else {
	
		return true;
		
	}
}
		

function checkValue(thisString) {

	var isNum = true;
	var stringLen = thisString.length;
	
	if(stringLen == 0) {
	
		isNum = false;
		
	} else {
	
		for(count = 0; count < stringLen; count++) {
	
			if(!(checkNum(thisString.charAt(count)))) {
		
				isNum = false;
				break;
		
			}	
		}
	}
	
	return isNum;
	
}



function calculateBodyFat() {

	form = document.IronPointForm;
	weight = form.Weight.value;
	if (form.Weight.value == "")
	{
		weight = form.WeightKg.value;
		if (form.WeightKg.value != "")	
			weight = weight * 2.2;
		
	}
	waist = form.Waist.value;
	if (form.Waist.value == "")
	{
		waist = form.Waist1.value;
		if (form.Waist1.value != "")	
			waist = waist / 2.54;
		
	}
	wrist = form.Wrist.value;
	if (form.Wrist.value == "")
	{
		wrist = form.Wrist1.value;
		if (form.Wrist1.value != "")	
			wrist = wrist / 2.54;
		
	}
	hips = form.Hips.value;
	if (form.Hips.value == "")
	{
		hips = form.Hips1.value;
		if (form.Hips1.value != "")	
			hips = hips / 2.54;
		
	}
	forearm = form.Forearm.value;
	if (form.Forearm.value == "")
	{
		forearm = form.Forearm1.value;
		if (form.Forearm1.value != "")	
			forearm = forearm / 2.54;
		
	}
	isFemale = 0;
	bodyfat = 0;
	
	if(form.Gender[1].checked) {
		isFemale = 1;
	}

	formInvalid = 0;

	field1 = '';
	field2 = '';
	field3 = '';
	field4 = '';
	field5 = '';

	if(!(checkValue(weight))) {
		field1 = 'weight in pounds, ';
		formInvalid = 1;
	}

	if(!(checkValue(waist))) {
		field2 = 'waist size, ';
		formInvalid = 1;
	}

	if(!(checkValue(wrist)) && isFemale) {
		field3 = 'wrist circumference, ';
		formInvalid = 1;
	}

	if(!(checkValue(hips)) && isFemale) {
		field4 = 'hips circumference, ';
		formInvalid = 1;
	}

	if(!(checkValue(forearm)) && isFemale) {
		field5 = 'forearm circumference, ';
		formInvalid = 1;
	}


	if(formInvalid) {
	
		message = 'Please enter the following required information: ' + field1 + field2 + field3 + field4 + field5;

		message = message.substring(0, (message.length - 2)) + '.';
	
		alert(message);
	
	} else {

		if(isFemale) {
		
			bodyfat = ( (weight - ( ( ( ((weight * 0.732) + 8.987) + (wrist / 3.14) ) - (waist * 0.157) ) - (hips * 0.249) ) + (forearm * 0.434) ) * 100) / weight;
		
		} else {
		
 	 		bodyfat = ((weight - (((weight * 1.082) + 94.42) - (waist * 4.15))) * 100) / weight;
		}
		
		if(!(isFemale)) {
		
			form.Wrist.value = '';
			form.Hips.value = '';
			form.Forearm.value = '';
			form.Wrist1.value = '';
			form.Hips1.value = '';
			form.Forearm1.value = '';
		
		}
		
		form.BodyFat.value = Math.floor(bodyfat);
	 
	}	
}